1. Field of the Invention
The present invention relates to a reference system for a track working machine comprising a vertically and/or laterally adjustable working tool unit, which comprises a front carriage spaced from a front end of the machine and being movable independently thereof, wireless remote control means mounted on the machine and controlling the independent movement of the front carriage, an emitter of a reference guide beam mounted on the front carriage for emitting the reference guide beam towards the machine, a reference means mounted on the machine and controlling the vertical and/or lateral adjustment of the working tool unit, and a reference guide beam receiver associated with the reference means and arranged on the machine for receiving the reference guide beam from the emitter.
2. Description of the Prior Art
A reference system of this general type has been disclosed in U.S. Pat. No. 3,706,284, dated Dec. 19, 1972. As described in this patent, a track tamper carries a reference means comprising tensioned reference wires extending between the front and rear undercarriages supporting the tamper for movement along a track, and a reference guide laser beam extends laterally of the reference means and serves as reference basis therefor. The laser beam is emitted from a laser beam emitter mounted on the rearmost undercarriage of the machine, and this emitter is remote-controllably positionable for sighting a laser beam receiver. This target receiver is arranged in the front portion of the machine and is transversely displaceable by a spindle drive to provide a fixed target. The machine operator can effectuate the focussing by means of a television receiver and a reproducing instrument. In one embodiment, a front carriage precedes the machine in the operating direction, the front carriage being equipped with a laser beam emitter and a telescope serving to focus the reference guide beam emitted from the emitter on the receiver mounted on the machine. A drive on the front carriage is remote-controllable by radio. This known reference system has the disadvantage of making it necessary for the tamper operator to walk to the front carriage in order to focus the emitter on the receiver.